The invention relates to a steering column arrangement for a motor vehicle.
A steering column of the generic type is known, for example, from German patent document DE 10 2006 009 304 B3. It comprises a console on the vehicle side, at which an outer tube of a steering column mounting a steering shaft can be fixed in a releasable manner by means of a clamping device. Respective laminated disk packs are thereby associated with the clamping device, which packs are fastened on the console side or on the steering shaft side and cooperate with each other in a clamping manner. So as to achieve a certain resilience with a force application of the steering column caused by an accident, at least one blade of the one laminated disk pack can be deflected when a load acting on the steering column in the direction of its longitudinal center axis in the transverse axis to the steering column longitudinal center axis exceeds a limit.
One object of the present invention is to provide a steering column arrangement for a motor vehicle (in particular a passenger vehicle) in which axial displacement of the outer tube caused by an accident is limited in a particularly advantageous manner.
This and other objects and advantages are achieved by the steering column arrangement according to the invention, in which the clamping device comprises at least one clamping wedge arrangement, which generates an increased holding force with an axial displacement of the outer tube caused by an accident. In other words, it is provided according to the invention to generate an increased clamping force or holding force of the clamping device in that a corresponding clamping wedge arrangement is provided, which generates an increased holding force between the console on the vehicle side and for example the outer tube of the steering column with an axial forward dislocation of the outer tube.
During the axial displacement of the outer tube, the increased holding force or clamping force of the clamping device is thereby generated in a simple and reliable manner in that clamping wedges corresponding to each other in a corresponding manner or other means of the clamping wedge arrangement are displaced against each other correspondingly, which leads to the increased holding force, which acts essentially transversely to the axial displacement or forward dislocation of the outer tube
In a further arrangement of the invention, it has furthermore been shown to be advantageous if the clamping wedge arrangement comprises two clamping wedges arranged laterally of the outer tube, which cooperate with corresponding console wedge legs of the console for generating the holding force during an axial displacement of the outer tube caused by an accident. These clamping wedges can be produced in a particularly simple and cost-efficient manner and can generate the increased holding force or clamping force of the clamping device in a particularly simple and advantageous manner, by displacing these against the corresponding console wedge legs of the console. It is however also conceivable to arrange only a single clamping wedge laterally of the outer tube in a constructive simplification of the clamping wedge arrangement.
It has further been shown to be advantageous if the clamping wedges can be displaced with the outer tube in its axial direction. In other words, it has been shown to be particularly advantageous if the initial movement of the outer tube is transferred directly or indirectly to the clamping wedges with a force application caused by an accident, whereby the clamping wedges are displaced relative to the corresponding console wedge legs, so as to generate the increased holding or clamping force hereby.
In a further arrangement of the invention, a higher friction coefficient is provided between the clamping wedges and the outer tube than between the clamping wedges and the respectively corresponding console wedge legs. It is ensured in this manner that the clamping wedges are taken along therewith during a forward dislocation of the outer tube caused by an accident, while the correspondingly desired displacement takes place relative to the corresponding console wedge legs for generating the holding force acting transversely to the forward dislocation.
A further advantageous embodiment provides that the clamping wedges are provided with elongated holes proceeding in the axial direction of the tube, through which passes a clamping bolt of the clamping device. In this manner, a particularly good hold or guide of the clamping wedge is given with an axial forward dislocation or displacement of the outer tube—and a displacement of the clamping wedges in conjunction therewith.
When a holding limit force is exceeded, it has been shown to be advantageous in a further arrangement of the invention if a plastic deformation takes place in the region of the clamping device. In this manner, a form-fit blockade of the clamping system or of the clamping device is achieved, which is desired for the further progress of the accident scenario.
The outer tube can be formed in one piece. In a further arrangement of the invention, it is however formed in several parts, wherein a first outer tube part can be loaded with an increased holding force of the clamping device during an axial displacement of the outer tube caused by an accident, and the other outer tube can be moved relative to the first outer tube while absorbing energy. In other words, a slight movement of the first outer tube part initially takes place during a force application caused by an accident, until this is fixed correspondingly by the increased holding force, whereafter the relative movement of the first outer tube part can take place by means of energy absorption. A particularly advantageous force progression, possibly in stages, can be achieved hereby while absorbing impact energy.
It is further advantageous if a further clamping element of the clamping device is arranged on the outside of the respective console wedge leg. The design of a clamping element in the shape of a wedge is especially advantageous if an especially good holding force is necessary in the case of a crash for avoiding an undesired height displacement of the outer tube. It is however generally also conceivable to design the outer side of the console wedge leg or/and the inner side of the clamping element parallel to the outer tube. It can be seen to be advantageous thereby if the outer side and/or the inner side are designed in a friction-increasing manner, for example by means of a corresponding coating. This particularly ensures the remaining in the adjusted height displacement position in the regular drive operation.
It has finally been shown to be advantageous if the console wedge legs have a respective stop, by which an axial displacement of the clamping wedges can be limited. A maximum displacement path of a maximum forward dislocation of the outer tube can hereby be adjusted in a particularly simple manner. A limitation of the maximum wedge forces introduced into the clamping system can hereby also be achieved.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.